@cesium/engine
Version:
CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.
633 lines (553 loc) • 19.9 kB
JavaScript
import earcut from "earcut";
import Cartesian2 from "./Cartesian2.js";
import Cartesian3 from "./Cartesian3.js";
import Cartographic from "./Cartographic.js";
import Check from "./Check.js";
import ComponentDatatype from "./ComponentDatatype.js";
import defined from "./defined.js";
import Ellipsoid from "./Ellipsoid.js";
import EllipsoidRhumbLine from "./EllipsoidRhumbLine.js";
import Geometry from "./Geometry.js";
import GeometryAttribute from "./GeometryAttribute.js";
import CesiumMath from "./Math.js";
import PrimitiveType from "./PrimitiveType.js";
import WindingOrder from "./WindingOrder.js";
const scaleToGeodeticHeightN = new Cartesian3();
const scaleToGeodeticHeightP = new Cartesian3();
/**
* @private
*/
const PolygonPipeline = {};
/**
* @exception {DeveloperError} At least three positions are required.
*/
PolygonPipeline.computeArea2D = function (positions) {
//>>includeStart('debug', pragmas.debug);
Check.defined("positions", positions);
Check.typeOf.number.greaterThanOrEquals(
"positions.length",
positions.length,
3,
);
//>>includeEnd('debug');
const length = positions.length;
let area = 0.0;
for (let i0 = length - 1, i1 = 0; i1 < length; i0 = i1++) {
const v0 = positions[i0];
const v1 = positions[i1];
area += v0.x * v1.y - v1.x * v0.y;
}
return area * 0.5;
};
/**
* @returns {WindingOrder} The winding order.
*
* @exception {DeveloperError} At least three positions are required.
*/
PolygonPipeline.computeWindingOrder2D = function (positions) {
const area = PolygonPipeline.computeArea2D(positions);
return area > 0.0 ? WindingOrder.COUNTER_CLOCKWISE : WindingOrder.CLOCKWISE;
};
/**
* Triangulate a polygon.
*
* @param {Cartesian2[]} positions Cartesian2 array containing the vertices of the polygon
* @param {number[]} [holes] An array of the staring indices of the holes.
* @returns {number[]} Index array representing triangles that fill the polygon
*/
PolygonPipeline.triangulate = function (positions, holes) {
//>>includeStart('debug', pragmas.debug);
Check.defined("positions", positions);
//>>includeEnd('debug');
const flattenedPositions = Cartesian2.packArray(positions);
return earcut(flattenedPositions, holes, 2);
};
const subdivisionV0Scratch = new Cartesian3();
const subdivisionV1Scratch = new Cartesian3();
const subdivisionV2Scratch = new Cartesian3();
const subdivisionS0Scratch = new Cartesian3();
const subdivisionS1Scratch = new Cartesian3();
const subdivisionS2Scratch = new Cartesian3();
const subdivisionMidScratch = new Cartesian3();
const subdivisionT0Scratch = new Cartesian2();
const subdivisionT1Scratch = new Cartesian2();
const subdivisionT2Scratch = new Cartesian2();
const subdivisionTexcoordMidScratch = new Cartesian2();
/**
* Subdivides positions and raises points to the surface of the ellipsoid.
*
* @param {Ellipsoid} ellipsoid The ellipsoid the polygon in on.
* @param {Cartesian3[]} positions An array of {@link Cartesian3} positions of the polygon.
* @param {number[]} indices An array of indices that determines the triangles in the polygon.
* @param {Cartesian2[]} texcoords An optional array of {@link Cartesian2} texture coordinates of the polygon.
* @param {number} [granularity=CesiumMath.RADIANS_PER_DEGREE] The distance, in radians, between each latitude and longitude. Determines the number of positions in the buffer.
*
* @exception {DeveloperError} At least three indices are required.
* @exception {DeveloperError} The number of indices must be divisable by three.
* @exception {DeveloperError} Granularity must be greater than zero.
*/
PolygonPipeline.computeSubdivision = function (
ellipsoid,
positions,
indices,
texcoords,
granularity,
) {
granularity = granularity ?? CesiumMath.RADIANS_PER_DEGREE;
const hasTexcoords = defined(texcoords);
//>>includeStart('debug', pragmas.debug);
Check.typeOf.object("ellipsoid", ellipsoid);
Check.defined("positions", positions);
Check.defined("indices", indices);
Check.typeOf.number.greaterThanOrEquals("indices.length", indices.length, 3);
Check.typeOf.number.equals("indices.length % 3", "0", indices.length % 3, 0);
Check.typeOf.number.greaterThan("granularity", granularity, 0.0);
//>>includeEnd('debug');
// triangles that need (or might need) to be subdivided.
const triangles = indices.slice(0);
// New positions due to edge splits are appended to the positions list.
let i;
const length = positions.length;
const subdividedPositions = new Array(length * 3);
const subdividedTexcoords = new Array(length * 2);
let q = 0;
let p = 0;
for (i = 0; i < length; i++) {
const item = positions[i];
subdividedPositions[q++] = item.x;
subdividedPositions[q++] = item.y;
subdividedPositions[q++] = item.z;
if (hasTexcoords) {
const texcoordItem = texcoords[i];
subdividedTexcoords[p++] = texcoordItem.x;
subdividedTexcoords[p++] = texcoordItem.y;
}
}
const subdividedIndices = [];
// Used to make sure shared edges are not split more than once.
const edges = {};
const radius = ellipsoid.maximumRadius;
const minDistance = CesiumMath.chordLength(granularity, radius);
const minDistanceSqrd = minDistance * minDistance;
while (triangles.length > 0) {
const i2 = triangles.pop();
const i1 = triangles.pop();
const i0 = triangles.pop();
const v0 = Cartesian3.fromArray(
subdividedPositions,
i0 * 3,
subdivisionV0Scratch,
);
const v1 = Cartesian3.fromArray(
subdividedPositions,
i1 * 3,
subdivisionV1Scratch,
);
const v2 = Cartesian3.fromArray(
subdividedPositions,
i2 * 3,
subdivisionV2Scratch,
);
let t0, t1, t2;
if (hasTexcoords) {
t0 = Cartesian2.fromArray(
subdividedTexcoords,
i0 * 2,
subdivisionT0Scratch,
);
t1 = Cartesian2.fromArray(
subdividedTexcoords,
i1 * 2,
subdivisionT1Scratch,
);
t2 = Cartesian2.fromArray(
subdividedTexcoords,
i2 * 2,
subdivisionT2Scratch,
);
}
const s0 = Cartesian3.multiplyByScalar(
Cartesian3.normalize(v0, subdivisionS0Scratch),
radius,
subdivisionS0Scratch,
);
const s1 = Cartesian3.multiplyByScalar(
Cartesian3.normalize(v1, subdivisionS1Scratch),
radius,
subdivisionS1Scratch,
);
const s2 = Cartesian3.multiplyByScalar(
Cartesian3.normalize(v2, subdivisionS2Scratch),
radius,
subdivisionS2Scratch,
);
const g0 = Cartesian3.magnitudeSquared(
Cartesian3.subtract(s0, s1, subdivisionMidScratch),
);
const g1 = Cartesian3.magnitudeSquared(
Cartesian3.subtract(s1, s2, subdivisionMidScratch),
);
const g2 = Cartesian3.magnitudeSquared(
Cartesian3.subtract(s2, s0, subdivisionMidScratch),
);
const max = Math.max(g0, g1, g2);
let edge;
let mid;
let midTexcoord;
// if the max length squared of a triangle edge is greater than the chord length of squared
// of the granularity, subdivide the triangle
if (max > minDistanceSqrd) {
if (g0 === max) {
edge = `${Math.min(i0, i1)} ${Math.max(i0, i1)}`;
i = edges[edge];
if (!defined(i)) {
mid = Cartesian3.add(v0, v1, subdivisionMidScratch);
Cartesian3.multiplyByScalar(mid, 0.5, mid);
subdividedPositions.push(mid.x, mid.y, mid.z);
i = subdividedPositions.length / 3 - 1;
edges[edge] = i;
if (hasTexcoords) {
midTexcoord = Cartesian2.add(t0, t1, subdivisionTexcoordMidScratch);
Cartesian2.multiplyByScalar(midTexcoord, 0.5, midTexcoord);
subdividedTexcoords.push(midTexcoord.x, midTexcoord.y);
}
}
triangles.push(i0, i, i2);
triangles.push(i, i1, i2);
} else if (g1 === max) {
edge = `${Math.min(i1, i2)} ${Math.max(i1, i2)}`;
i = edges[edge];
if (!defined(i)) {
mid = Cartesian3.add(v1, v2, subdivisionMidScratch);
Cartesian3.multiplyByScalar(mid, 0.5, mid);
subdividedPositions.push(mid.x, mid.y, mid.z);
i = subdividedPositions.length / 3 - 1;
edges[edge] = i;
if (hasTexcoords) {
midTexcoord = Cartesian2.add(t1, t2, subdivisionTexcoordMidScratch);
Cartesian2.multiplyByScalar(midTexcoord, 0.5, midTexcoord);
subdividedTexcoords.push(midTexcoord.x, midTexcoord.y);
}
}
triangles.push(i1, i, i0);
triangles.push(i, i2, i0);
} else if (g2 === max) {
edge = `${Math.min(i2, i0)} ${Math.max(i2, i0)}`;
i = edges[edge];
if (!defined(i)) {
mid = Cartesian3.add(v2, v0, subdivisionMidScratch);
Cartesian3.multiplyByScalar(mid, 0.5, mid);
subdividedPositions.push(mid.x, mid.y, mid.z);
i = subdividedPositions.length / 3 - 1;
edges[edge] = i;
if (hasTexcoords) {
midTexcoord = Cartesian2.add(t2, t0, subdivisionTexcoordMidScratch);
Cartesian2.multiplyByScalar(midTexcoord, 0.5, midTexcoord);
subdividedTexcoords.push(midTexcoord.x, midTexcoord.y);
}
}
triangles.push(i2, i, i1);
triangles.push(i, i0, i1);
}
} else {
subdividedIndices.push(i0);
subdividedIndices.push(i1);
subdividedIndices.push(i2);
}
}
const geometryOptions = {
attributes: {
position: new GeometryAttribute({
componentDatatype: ComponentDatatype.DOUBLE,
componentsPerAttribute: 3,
values: subdividedPositions,
}),
},
indices: subdividedIndices,
primitiveType: PrimitiveType.TRIANGLES,
};
if (hasTexcoords) {
geometryOptions.attributes.st = new GeometryAttribute({
componentDatatype: ComponentDatatype.FLOAT,
componentsPerAttribute: 2,
values: subdividedTexcoords,
});
}
return new Geometry(geometryOptions);
};
const subdivisionC0Scratch = new Cartographic();
const subdivisionC1Scratch = new Cartographic();
const subdivisionC2Scratch = new Cartographic();
const subdivisionCartographicScratch = new Cartographic();
/**
* Subdivides positions on rhumb lines and raises points to the surface of the ellipsoid.
*
* @param {Ellipsoid} ellipsoid The ellipsoid the polygon in on.
* @param {Cartesian3[]} positions An array of {@link Cartesian3} positions of the polygon.
* @param {number[]} indices An array of indices that determines the triangles in the polygon.
* @param {Cartesian2[]} texcoords An optional array of {@link Cartesian2} texture coordinates of the polygon.
* @param {number} [granularity=CesiumMath.RADIANS_PER_DEGREE] The distance, in radians, between each latitude and longitude. Determines the number of positions in the buffer.
*
* @exception {DeveloperError} At least three indices are required.
* @exception {DeveloperError} The number of indices must be divisable by three.
* @exception {DeveloperError} Granularity must be greater than zero.
*/
PolygonPipeline.computeRhumbLineSubdivision = function (
ellipsoid,
positions,
indices,
texcoords,
granularity,
) {
granularity = granularity ?? CesiumMath.RADIANS_PER_DEGREE;
const hasTexcoords = defined(texcoords);
//>>includeStart('debug', pragmas.debug);
Check.typeOf.object("ellipsoid", ellipsoid);
Check.defined("positions", positions);
Check.defined("indices", indices);
Check.typeOf.number.greaterThanOrEquals("indices.length", indices.length, 3);
Check.typeOf.number.equals("indices.length % 3", "0", indices.length % 3, 0);
Check.typeOf.number.greaterThan("granularity", granularity, 0.0);
//>>includeEnd('debug');
// triangles that need (or might need) to be subdivided.
const triangles = indices.slice(0);
// New positions due to edge splits are appended to the positions list.
let i;
const length = positions.length;
const subdividedPositions = new Array(length * 3);
const subdividedTexcoords = new Array(length * 2);
let q = 0;
let p = 0;
for (i = 0; i < length; i++) {
const item = positions[i];
subdividedPositions[q++] = item.x;
subdividedPositions[q++] = item.y;
subdividedPositions[q++] = item.z;
if (hasTexcoords) {
const texcoordItem = texcoords[i];
subdividedTexcoords[p++] = texcoordItem.x;
subdividedTexcoords[p++] = texcoordItem.y;
}
}
const subdividedIndices = [];
// Used to make sure shared edges are not split more than once.
const edges = {};
const radius = ellipsoid.maximumRadius;
const minDistance = CesiumMath.chordLength(granularity, radius);
const rhumb0 = new EllipsoidRhumbLine(undefined, undefined, ellipsoid);
const rhumb1 = new EllipsoidRhumbLine(undefined, undefined, ellipsoid);
const rhumb2 = new EllipsoidRhumbLine(undefined, undefined, ellipsoid);
while (triangles.length > 0) {
const i2 = triangles.pop();
const i1 = triangles.pop();
const i0 = triangles.pop();
const v0 = Cartesian3.fromArray(
subdividedPositions,
i0 * 3,
subdivisionV0Scratch,
);
const v1 = Cartesian3.fromArray(
subdividedPositions,
i1 * 3,
subdivisionV1Scratch,
);
const v2 = Cartesian3.fromArray(
subdividedPositions,
i2 * 3,
subdivisionV2Scratch,
);
let t0, t1, t2;
if (hasTexcoords) {
t0 = Cartesian2.fromArray(
subdividedTexcoords,
i0 * 2,
subdivisionT0Scratch,
);
t1 = Cartesian2.fromArray(
subdividedTexcoords,
i1 * 2,
subdivisionT1Scratch,
);
t2 = Cartesian2.fromArray(
subdividedTexcoords,
i2 * 2,
subdivisionT2Scratch,
);
}
const c0 = ellipsoid.cartesianToCartographic(v0, subdivisionC0Scratch);
const c1 = ellipsoid.cartesianToCartographic(v1, subdivisionC1Scratch);
const c2 = ellipsoid.cartesianToCartographic(v2, subdivisionC2Scratch);
rhumb0.setEndPoints(c0, c1);
const g0 = rhumb0.surfaceDistance;
rhumb1.setEndPoints(c1, c2);
const g1 = rhumb1.surfaceDistance;
rhumb2.setEndPoints(c2, c0);
const g2 = rhumb2.surfaceDistance;
const max = Math.max(g0, g1, g2);
let edge;
let mid;
let midHeight;
let midCartesian3;
let midTexcoord;
// if the max length squared of a triangle edge is greater than granularity, subdivide the triangle
if (max > minDistance) {
if (g0 === max) {
edge = `${Math.min(i0, i1)} ${Math.max(i0, i1)}`;
i = edges[edge];
if (!defined(i)) {
mid = rhumb0.interpolateUsingFraction(
0.5,
subdivisionCartographicScratch,
);
midHeight = (c0.height + c1.height) * 0.5;
midCartesian3 = Cartesian3.fromRadians(
mid.longitude,
mid.latitude,
midHeight,
ellipsoid,
subdivisionMidScratch,
);
subdividedPositions.push(
midCartesian3.x,
midCartesian3.y,
midCartesian3.z,
);
i = subdividedPositions.length / 3 - 1;
edges[edge] = i;
if (hasTexcoords) {
midTexcoord = Cartesian2.add(t0, t1, subdivisionTexcoordMidScratch);
Cartesian2.multiplyByScalar(midTexcoord, 0.5, midTexcoord);
subdividedTexcoords.push(midTexcoord.x, midTexcoord.y);
}
}
triangles.push(i0, i, i2);
triangles.push(i, i1, i2);
} else if (g1 === max) {
edge = `${Math.min(i1, i2)} ${Math.max(i1, i2)}`;
i = edges[edge];
if (!defined(i)) {
mid = rhumb1.interpolateUsingFraction(
0.5,
subdivisionCartographicScratch,
);
midHeight = (c1.height + c2.height) * 0.5;
midCartesian3 = Cartesian3.fromRadians(
mid.longitude,
mid.latitude,
midHeight,
ellipsoid,
subdivisionMidScratch,
);
subdividedPositions.push(
midCartesian3.x,
midCartesian3.y,
midCartesian3.z,
);
i = subdividedPositions.length / 3 - 1;
edges[edge] = i;
if (hasTexcoords) {
midTexcoord = Cartesian2.add(t1, t2, subdivisionTexcoordMidScratch);
Cartesian2.multiplyByScalar(midTexcoord, 0.5, midTexcoord);
subdividedTexcoords.push(midTexcoord.x, midTexcoord.y);
}
}
triangles.push(i1, i, i0);
triangles.push(i, i2, i0);
} else if (g2 === max) {
edge = `${Math.min(i2, i0)} ${Math.max(i2, i0)}`;
i = edges[edge];
if (!defined(i)) {
mid = rhumb2.interpolateUsingFraction(
0.5,
subdivisionCartographicScratch,
);
midHeight = (c2.height + c0.height) * 0.5;
midCartesian3 = Cartesian3.fromRadians(
mid.longitude,
mid.latitude,
midHeight,
ellipsoid,
subdivisionMidScratch,
);
subdividedPositions.push(
midCartesian3.x,
midCartesian3.y,
midCartesian3.z,
);
i = subdividedPositions.length / 3 - 1;
edges[edge] = i;
if (hasTexcoords) {
midTexcoord = Cartesian2.add(t2, t0, subdivisionTexcoordMidScratch);
Cartesian2.multiplyByScalar(midTexcoord, 0.5, midTexcoord);
subdividedTexcoords.push(midTexcoord.x, midTexcoord.y);
}
}
triangles.push(i2, i, i1);
triangles.push(i, i0, i1);
}
} else {
subdividedIndices.push(i0);
subdividedIndices.push(i1);
subdividedIndices.push(i2);
}
}
const geometryOptions = {
attributes: {
position: new GeometryAttribute({
componentDatatype: ComponentDatatype.DOUBLE,
componentsPerAttribute: 3,
values: subdividedPositions,
}),
},
indices: subdividedIndices,
primitiveType: PrimitiveType.TRIANGLES,
};
if (hasTexcoords) {
geometryOptions.attributes.st = new GeometryAttribute({
componentDatatype: ComponentDatatype.FLOAT,
componentsPerAttribute: 2,
values: subdividedTexcoords,
});
}
return new Geometry(geometryOptions);
};
/**
* Scales each position of a geometry's position attribute to a height, in place.
*
* @param {number[]} positions The array of numbers representing the positions to be scaled
* @param {number} [height=0.0] The desired height to add to the positions
* @param {Ellipsoid} [ellipsoid=Ellipsoid.default] The ellipsoid on which the positions lie.
* @param {boolean} [scaleToSurface=true] <code>true</code> if the positions need to be scaled to the surface before the height is added.
* @returns {number[]} The input array of positions, scaled to height
*/
PolygonPipeline.scaleToGeodeticHeight = function (
positions,
height,
ellipsoid,
scaleToSurface,
) {
ellipsoid = ellipsoid ?? Ellipsoid.default;
let n = scaleToGeodeticHeightN;
let p = scaleToGeodeticHeightP;
height = height ?? 0.0;
scaleToSurface = scaleToSurface ?? true;
if (defined(positions)) {
const length = positions.length;
for (let i = 0; i < length; i += 3) {
Cartesian3.fromArray(positions, i, p);
if (scaleToSurface) {
p = ellipsoid.scaleToGeodeticSurface(p, p);
}
if (height !== 0) {
n = ellipsoid.geodeticSurfaceNormal(p, n);
Cartesian3.multiplyByScalar(n, height, n);
Cartesian3.add(p, n, p);
}
positions[i] = p.x;
positions[i + 1] = p.y;
positions[i + 2] = p.z;
}
}
return positions;
};
export default PolygonPipeline;